This section provides background information related to the present disclosure which is not necessarily prior art.
High voltage transformers in electrical distribution systems typically have loadbreak connectors connecting high voltage cables to the transformers. The loadbreak connectors have loadbreak bushings. In transformers having loadbreak bushings, it is difficult to obtain accurate and consistent transformer winding resistance test results. Most transformer winding resistance testers have a current source output and a separate voltage sense input to measure the resistance of the transformer winding only and ignores the resistance of the test probes.
When measuring the winding resistance of a transformer having loadbreak bushings, a conductive rod of some type, such as a ½ inch diameter rod, must be inserted into the bushing to make contact with the conductive portion of the bushing. This adds to the resistance of the test probe. This can introduce an unknown factor and error to the resistance test results due to the differences in resistivity of the materials of which the conductive rod can be made. The conductive rod can be made of any conductive material such as copper, steel or aluminum. Each of these materials has different resistivity and will therefore introduce an unknown amount of error to the winding resistance measurement. This invention will practically eliminate error introduced by the test probe.